Glossary

Pro Rata Share

Also known as: proportionate share, tenant's share

A tenant's proportionate percentage of a building or center's operating expenses and taxes, generally calculated as the tenant's rentable square footage divided by the property's total rentable square footage.

The denominator used in this calculation is a frequent source of dispute: some landlords use total building RSF (favoring accuracy but exposing the landlord to under-recovery during vacancy, absent a gross-up) while others use occupied RSF, which shifts more cost onto fewer paying tenants. Pro rata share changes whenever a tenant expands or contracts its premises, or when the building's total RSF is remeasured under an updated BOMA standard, both of which require corresponding adjustments to CAM billing and lease abstracts. Because pro rata share directly drives the dollar amount owed under a pass-through structure, errors in the underlying square footage figures compound into recurring billing inaccuracies until corrected.